Have some small trout, put them in a fireproof dish, with, all round, tomatoes cut in quarters, one banana cut in thin slices, tarragon and shallots finely chopped. Pour over all this a glass of dry white wine, season well, and cook very slowly; turn them carefully when they are about half done. When they are ready, remove the skins and keep the fish hot; let the sauce reduce a little more, then pass it through a fine sieve. Dispose the trout in the fireproof dish; add some sauce hollandaise to the sauce, little by little, over a very slow fire, whipping all the time. When it has the right consistency pour over the trout and serve at once.